The present invention relates to computer mice or track balls, and in particular to buttons on such devices.
In one type of computer mouse, a ball protrudes from the bottom of the mouse housing, and rolls across a supporting surface. The movement of the ball is typically detected by shafts which are in contact with the ball and turn an encoder wheel having a number of slots. Track balls will have a ball mounted on the top with the housing being stationary, but similarly operate with two encoder wheels at 90° angles to detect X and Y movement. Optical mice and trackballs have also been developed.
Such mice and track balls typically also have buttons which can be depressed or clicked by a user, and which depress a switch (microswitch, pancake, optical, etc.). These provide additional inputs to the computer, in addition to the position of the mouse or trackball. Some mouse designs have added a roller or wheel which can be used for such functions as scrolling or zooming. The roller is operated by a user finger much like a dial on a radio.
A button is typically formed by one or more plastic keyplates, which attach to the underside of the top housing of the mouse or trackball. The keyplate covers a part of the mouse, and there is a gap between the keyplate and the rest of the top housing, or adjacent keys. Beneath the keyplate, inside the device, a microswitch is mounted to be activated when the keyplate is depressed.